Okay, your breakdown is like this...
"A" block... Poly. Dodge/Desoto 270/315/325 Plymouth 318/326. Dodge Polys are closely related to early hemis, in the case of the 315/325 some actually had hemi heads! Polys have the distinctive scalloped covers. While the DeDodgo and Plymouth Polys are both "a" blocks, not much interchanges.
"LA" or "Late A" shares little with the early "a", cam gear sprocket and lifter bore size.
"B" block. This was developed by Plymouth in the fifties, No plymouths had hemis then. Starting in 1958, the 350 and 361 debuted.
"Raised B" debuted in 1959 with the 383 and 413 to replace the 392. The 383 was dropped, and 426 added to the lineup.
I think in '66 or '67 the "b" block 361 was bored to 383. This was NOT the same animal as the earlier RB 383- the two motors have different bores and strokes.
KFD